package J11_9;

import java.util.Scanner;

public class Test1 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int a = in.nextInt();
        int b = in.nextInt();
        if (a > b) {
            System.out.println(a - b);
        } else {
            System.out.println(0);
        }
    }
}
